Elastic fluid engine



u 1945- s. L. KNOX 2,405,359

' ELASTIC FLUI-D ENGINE I Filed Feb. 16, 1945 4 Sheets-Sheet 1 v s. L G. KNOX ELASTIC/FLUID ENGINE Filed Feb. 16, 1945 4 Sheets-Sheet 2 A. 6, 1 946. s. G. KNOX ELASTIC FLUID ENGINE Filed Feb. 16, 1945 4 Sheets-Sheet 5 Aug; a, 1946. N X 2,405,359

ELASTIC FLUID ENGINE Filed Feb. 16, 1945 4 Sheets-Sheet 4 Patented Aug. 6, 1946 FICE ELASTIC FLUID ENGINE Samuel Lippincott Griswold Knox, New York, N. Y.

x Application February 16, 1945, Serial No. 578,160

, 7 Claims. (o1.-121 101) This invention relates to improvements in elas- I tic fiuid engines, and more particularly to reciprocating engines operated by a compressed elastic fluid such as steam in which the functions of the usual valves for controlling steam distribution are performed by'the piston which is given elliptical motion in its cylinder.

In conventional reciprocating engines, distribution of steam to the cylinder is controlled by valves operating with angles of advance relative to piston, thereby to admit steam to the cylinder and thereafter to effect steam cut-off so that the expansion of the steam will be translated into useful mechanical work. The present invention has for its principal object the simplification of steam engine design and operation through the provision of an engine which is valveless in the sense that it has no valve, separate from the piston, for controlling steam distribution, and in which the functions of a valve in eifecting distribution are performed by the piston itself. Mor

specifically, the present invention provides a reciprocating engine in which the piston is given elliptical motion and wherein such motion is utilized, in conjunction with ported skirts on the piston and ported sleeves which ar interposed between the piston and its cylinder, to effect the necessary steam distribution for either direction of engine operation. According to a further feature of the invention, the ported sleeves aforesaid are so constructed and arranged as to be displaceable relatively to each other and to the piston for the purpose of controlling the direction of engine operation and also to regulate steam cut-off.

Other objects will be in part obvious and in part hereinafter pointed out in connection with the following analysis of thi invention wherein is illustrated an embodiment of the invention in detail.

In the drawings Fig. 1 is a part sectioned elevation of a twocylinder engine according to the invention taken generally on line l-l of Fig. 2, which shows a typical engine arrangement of cylinder block, cross-head, connecting rod and crankshaft, and which moreover illustrates in detail the sleeve displacing mechanism of the present invention.

Fig. 2 is a section through. one cylinder of the engine taken on line 2--2 ofFig. 1, showing the piston in its head-end dead-center position, and further illustrating sleeve mounting and arrangement relative to piston according to the invention.

. Fig. 3 is a section taken'online 3--,3 "of Fig. 1.

I .2 v V Figs.'4, 4a, 4b, 4c, 4d, 46 are developed view of a portion of the piston and sleeves as the latter are seen from the interior of the piston, showing progressive positions .of piston ports to sleeve ports through one-half rotation of the crank shaft, the displacement of the sleeves correspondingto counterclockwise rotation of the crank shaft as viewed in Fig. 2.

5 is a view corresp nding to Fig. 4, showing opposite displacement of the sleeves to effect opposite operation of the engine.

As with other engines, an engine according to th present invention may be constructed with a single cylinder or with multiple cylinders. However, since a two-cylinder double acting arrangement represents the simplest self-starting construction, the following description will be based on this type. It will be noted also that the invention is not limited to the vertical engine arrangement as illustrated.

Referring in detail to the drawings wherein like reference characters designate like parts throughout the several views, with the letters H and C designating head and crank end parts, respectively, and thus differentiating opposite, similarly numbered parts, the two-cylinder engine shown comprises a cylinder block 6 having two elongated cylinder spaces, in each of which operates apiston l which, as shown in Fig. 2, is formed with a long skirt 7H at its head end and a similar skirt '7C'at its crank end. A piston rod 8 connects the pison to the cross head 9 and th latter is connected by connecting rod ill to the crank shaft ll turning in bearings generally as shown. The aforesaid engine parts are arranged as sual to convert the expansive force of th steam to rotative force on the crank shaft H. In Fig. ,2 reference characters I2, I 3 designate, respectively, coaxially related head and crank end sleeves which are interposed between the piston and its cylinder, the sleeves having their adjacent ends lapped as shown and being mounted in the cylinder block for angular (circumferential) displacement relative to each other and hence to the piston l.

Oscillating motion in addition to the usual translation of the piston is obtained by incorporating bevel gear teeth 14 built into the connecting rod I0 which mesh with the teeth of a bevel pinion sector [.5 which is afiixed to the lower end of the piston rod 8. The teeth l4, 15 are located between the cross head and crank pin of the connecting rod I0, so that as the crankshaft rotates, motion of the connecting rod in a plane transverse to vertical translation will produce cate through branch pipes l8a, |8b (Fig. 1). The chests open respectively into annular' hea'd and crank end steam passages lB I-I, l-9 C formed 7 in the cylinder wall. The latter passages oemmunicate through openings (not shown) provided shown to be formed as parts of a unitary casting secured to the cylinder block side. The casting in its intermediate portion provides a bearing for a tubular sleeve 2'! mounted for both rotary and reciprocating motion, through the bore of which extends valve stem 11a of poppet valve ll. The tubular stem 21 is keyed to a bevel segment 28 meshing with a bevel pinion 29 journaled for'rotation about a fixed axis having bearing in the chest"casting. The bevel pinion is fast on a cylindrical pinion 30 (Fig. 3), the teeth of which mesh with upper and lower racks- SIH, 31c, which are pivotally joined at theirends to studs 32H, 32C aihxed to the sleeves 12,13, respectively. Thus, by reference to Fig. 1,

it will be observed that counterclockwise rotain the cylinder wall sides "with a 'plurality of-' head and crank end admission ports 201-1, 2516;

which are formed in the sleeves l2, l3,respc-' .tively, andare arranged'inciroular series therein. TheJpiston skirts are also provided with alike number of head andcrank'end ports 21H, ZIC',

respectively, similarly arranged in circular series faridiunctioning to pass'iste'am' through the pisskirts to the finterior er the piston. The at "elliptical motion of the' pisto n is 'utili'z'edto open and close 'thd'piston ports to the admission ports H, 20C of the sleeves l2; 13, respectively," "These sleeves arepositioned in a manner to" be described so that admission of steam occurs just before piston dead-center and thatjthe' point of cut-"off is regulated by the angula'r' iposition' of the sleeves relative to each other andjtoth'episton.""* ij I In addition to the steam admission ports 20H, 20C'provided' therein, the sleeves l2, l3 are-each provided '"with'two supplementary admission ports, the supplementary "ports 22H-'of"sleeve 'l2'a'n'd the likeports 22C offsl'ee've 13 'bein'gmore admission ports whereby the desirable'delayed cut-off features disclosed and claimed in" my prior Patent No; 2,091,996; dated September '7, 1937; areobtainedand the engine will be self starting 'in spite-of early cut-off. The supplementary ports 22H; 226 are of restricted size, 'as-shown, and are 'thus unable to pass any substantial amount of'steam when theengine'is running at normal speed; 1 f

The" cylinders are exhausted by conventional uniflow ports 2311;"2'30 inthe upper and lower ends of the sleeves' l2, l3; respectively, which are-controlled by the 'endsof the piston skirts, and -which open into the exhaust jacket space 24. In order-to delay thesta'rt of compression, advantage is taken of the piston ports 241-1, 210 and the elliptical travel'of the-piston by providing aplurality of --auxiliaryexhaust ports 251-1 256 inthe head and crank'end sleeves l2, l3. Both the "uniflow exhaust and the auxiliary exhaust ports are arranged in circular series, generally "as shown. While-not necessary to engine-operenginewp'eration, 'arid alsotovary the cut-off;

Referring to Figsg 'l-3g th e" chests 5H,- I-8C are means for varying cutoff through non orthe bevel pinion 29 incident to leftwise I turningv of sleeve 21 results in displacement of the upper rack HR to the left and corresponding displacement of the lower rack 34C. to the right; As the racks areafiixed to. the'sleeves, the latter are correspondingly displaced in opposite dire'c'tionsand by a given amount depending on the degree of rotationofsleevefl.

The tubular sleeve 27 terminates at its upper endin a head 21a, againstwhich ajhead l'lb, formed at the upper end of the poppet stem Ila is secured, whereby lowering'movement or the sleeve'results in corresponding lowering'movement of the stem and opening of the poppet valve H. The sleeve head" carries a yoked clevis 34 between the upper leg' ends of which is pivoted one end of a duplex link 35. The other end of the link 35 is pivotedtothe lower end of' an arm 36, the upper end of the latter being pivotally connected to a swiveltl turning ina fixed support 38; 'An operating lever 60 having a handle at its free end is formed integral with the duplex link 35 and carries a pivoted locking handle 4| for a'pawl 42,'the latter being adapted to ratchet with teeth (iS'eXtending along an arcuate edge formed on an extended portion of the arm 36. -By the above'described arrangement, raising movement of operating lever 40 results in lowering movement of both tubular stem 21 and poppet stem Na, and hence in opening'of the poppet valve H, the linkage system being such'th'at raising movement of the lever results in graduated openingof the-valve asrequired to efiect throttling. Locking handle operates through pawl 42 and ratchet 43 to hold thepoppet valve to anydesired degree of opening.- 'Inaddition to its raising movement as aforesaid, the operating leveris also bodily turnable to each side of a normal central position, the latter movement resulting in turning of the bevel segments ZB-and angular displacement oithe sleeves l2, 13in opposite direction as-aforesaid. Accordingly, the described arrangement provides a'sin gle control for effecting throttling and for determining the direction of engine operation. 5 And, due to the fact that displacement'of the sleeves 42,13 is also employed to 'vary-cut off," the single control means as aforesaid additionally provides angulardisplacement of the-sleeves] 4 I Figs; 4-, 411,411, 40; 4d; 46 illustrate the progres sive positions of the piston ports to sleeve ports through one-half rotation of the crank shaft; and will serve to explain the operation of the engine; In Fig. '4 the piston I is shownin'its head-end dead-center position; and the sleeves l 2, '--l 3 are shown as displaced relatively to each other from their mean or central positions to sleeve posit-ions corresponding tocounterclockwi-se direction of rotation of the engine as indicated by crank shaft arrow (Fig. 2). With the motion of the "piston being such-thatany point on the p'iston,and specifically-thepoint P thereon, moves in an elliptical path, the motion of the piston is designated in the said figures by adot and dash ellipse, and thecounterclockwise direction ofmotion by the applied arrow. For such direction of rotation, the supplementary port 22H tothe right of thecenter line of sleeve I2, and the supplementary port 220 to the left of the center line of sleeve l3 .are operative, the alternate set of supplementary ports being inoperative, i, e, at all times coverediby the piston. Y i I.

In Fig. 4 it will be'seen that the piston ports 2IH have just opened to sleeve ports 20H, with the'engine crank on dead-center. No other ports are open except uniflow exhaust ports 23C at the crank or opposite end ,Ofthe cylinder. Fig; 4a shows a further advanced position with piston ports .2 l H open to sleeve ports 20H. Atthe oppositeend of the cylinder themain exhaust ports 230 have been closed by the piston skirt 70. However, at this point of piston travel, the piston ports ZIC are starting to open to the.v auxiliary exhaust ports 250. thus delaying the start of compression at the crank end of the cylinder.

. Fig. 4b shows the approach to the cut-olT of steam at the upper or head end of the cylinder, and alsothat the operative supplementary admission port 22H is admitting a small quantity of steam, thereby delaying cut-off for self-starting. At the crank end of the cylinder, auxiliary exhaust through ports 250 is still taking place. Fig. 4c shows that main cut-ofi has taken place at the head end of the cylinder except for supplementary admission through small port 22H. At the lower end of the cylinder, auxiliary ports 250 have been covered so that further down movement'of the piston eiTects compression therein. Fig. 4d shows cut-off of the operative supplementary port 220, Comparison of piston position in Fig. 4d with that shown in Fig. 4b illustrates the difference between the main and supplementary cut-off. Fig. 4e shows the uniflow exhaust ports 23Hat the head end of the cylinder open. At the crank end, the piston ports 2|C are just approaching sleeve ports 200 so that main admission to the crank end of the cylinder is about to begin. I

With the aforesaid views showing successive positions of the piston and sleeve ports through one-half revolution of the crank shaft, by simple reversal they also illustrate successive piston and port positions for the other half of the crank shaft revolution.

Fig, is a view corresponding to Fig. 4 but illustrating displacement of the upper sleeve l2 to the right and of the lower sleeve l3 to the left of their relative position hown in Fig. 4, as required for rotation of the engine in opposite direction. In the View, the motion of the piston is in clockwise direction, with the point P describing the elliptical path shown. Inasmuch as relative position of piston and sleeve ports follows generally that described in connection with Figs. 44e, inclusive, with the diiference that the piston in Fig. 5 is moving clockwise, no detailed description or repeated illustrations for the opposite direction of rotation and with the sleeves positioned as in Fig, 5 is believed to be necessary.

Without further analysis it will be self-evident from the above description that an engine according to the invention is valveless in the sense that it employs no valves separate from the piston, and that the control-and. distribution of the steam to the cylinders thereof is'obtained through the elliptical motion of the iston, in conjunction with the use of ported piston skirts andported sleeves which. are interposed between the skirted pistonandits cylinder, vIn addition to simplifi cation of steamengine design and operation, the invention further provides an extremely simple yet e'fiective means to vary the p'oint;'of,.cut-..off

pedient ofl displacing the sleeves .by a given amount to opposite sides oftheirnormal central position; The invention also makes use of; the motion of the piston in i delaying the. start of-conipression,.-as well as to-efiiect delayedcut-oii and hence self-starting of thezeng'ine; 1 f;

While the above description refers to the .use

of ported sleeves by which the desirablevariable cutoff: and reversing- 1 features are in; part achieved, such sleeves are not essential,to.an-,.en-.

gine operatingas' described where the variable cutoff and reversing provisions are'notrequired,

and hence may be omitted without departing from the scope and spirit of the present invention.' Moreover, although the engine as described has been referred to specificallyas a steam engine, it can of course be operated by the pressure of elastic fluids other than steam. Hence, it is to be understood that where steam is used throughout the specification and inthe claims, such use is made for convenienceon-ly and is intended to designate and embrace all forms of elastic fluids capable ,of operating en gines of the character herein described.

It is also to be understood thatthe word elliptical as used in the foregoing description and in the appended claims to descri'be'the motion or path of travel of the piston is employed for convenience to define its simultaneous reciprocating and rotating'movement or travel, which'may not follow a true geometric ellipse. Accordingly the expressions elliptical motion and elliptical path as herein used are to be broadly construed to embrace any and all such motion or travel of the piston as results from its compounded reciprocating and rotative movement.

Moreover as many changes could be made in carrying out the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a reciprocating engine, a cylinder, a piston, the cylinder having steam supply and exhaust openings, a sleeve interposed between the piston and the cylinder, the sleeve having admission, supplementary exhaust and main unifiow exhaust ports opening to the cylinder supply and exhaust openings and to the cylinder space, the piston having end skirtsv provided with ports opening to the interior of the skirted ends thereof, the sleeve and piston ports having a relationship such that the piston ports open and close the interior of the skirted ends of the piston to the steam supply and exhaust openings during motion of the piston in an elliptical path, and

placeable sleeves interposed cylinder, the'cylinder having steam supply and means responsive to, the, operation of the engine for imparting felliptical :motion, to the piston.

In 'a reciprocating engine, a, cylinder, 9. piston,- the cylinder havingsteam "supply and exhaust openings, a sleeve interposed between the pistonwand the cylinder, the sleeve having main admission, supplementary (admission, supplementary ..exhaust and'main -.uniflow exhaust ports'opening ;to the cylinder supply and exhaust openingsrespectively, and to the cylinder space, thepiston having end skirtsprovided with ports opening to theinteriorthereof; thesleeve and piston ports being'so related'and arranged that the pistonports open the interior of the skirted ends of the piston successively to the :main and supplementary"admission ports and to the exhaust portsof the sleeve upon motion of the-piston in an elliptical path, and means responsive to the operation of the engine tor-imparting ellipticalmotion to,therpiston. v

3. In a reciprocating double. acting engine, a cylinder, a-skirted piston, coaxial relatively disbetween piston and exhaust openings, the sleeves and the piston skirts being provided with ports for opening the interior of the skirted ends of the piston to the supply and exhaust openings, respectively, upon motion of the piston in an elliptical path, means responsive to engineeoperation for imparting elliptical motion to the piston, and means for displacing the sleeves an equal amount in opposite directions whereby to effect control of the direction of engine operation.

, 4, In a reciprocating double acting engine, a cylinder, a skirted piston, coaxial relatively displaceable sleeves interposed between piston and cylinden'the cylinder having steam supply and exhaust openings, skirts being provided'with ports for opening the interior of the skirted ends of the piston to the supply and exhaust openings, respectively, upon motion of the piston in an elliptical path, means responsive to engine operation for imparting elliptical motion to the piston, the relation and arrangement of sleeve ports to piston ports being such that opposite displacement of the sleeves to the sides of a mean position is required to effect engine operation in a given direction, and means for effecting opposite displacement of the sleeve the. sleeves and the piston 8 in either direction thereby to control the directionofengine operation. q

5. In a: reciprocating engine,-; a cylinder, a skirted piston, an angularly displaceable sleeve interposed between piston and cylinder, the ,cylinder having steam supply andexhaust openings, the sleeve, and the, pistonskirts being provided with cooperating ports adapted upon motion of the piston in an elliptical path to control admissionof steam to the interior of the skirted ends of the piston andto efiect steam cut-01f, means responsivetoengine operation for imparting elliptical motionto the piston, and means for effecting angular displacement of the sleeve thereby to vary the point of cut-off.

- 6. In a reciprocating double acting engine, a cylinder, a skirted piston, coaxial sleeves inter,- posed between piston and cylinder and being mounted for relative. angular displacement, the cylinderhaving' steamisupply and exhaust openings, the sleeve'and the piston skirts being provided with cooperating ports adapted, upon motion of the piston in' an elliptical path to control admission of steam tothe interior of the'skirted ends of the piston and to effect steam cut-off, means responsive to engine operation for imparting elliptical motion to the piston, and means for effecting relative angular displacement of the sleeves thereby to vary the point'of cut-off. 7. In a reciprocating double acting engine, a cylinder, a skirted piston, coaxial sleeves interposed between piston and cylinder and being mounted for relativeangular displacement, the cylinder having steam supply and exhaust openings, the sleeve and the piston skirts being provided with cooperating ports adapted upon motion of the piston in an elliptical path to control flow of steam to the interior of the skirted ends of the piston and said ports being arranged so that opposite angular displacement of the sleeves from a central position is required for operation of the engine in one direction and that reverse angular displacement of the sleeves from, said central position is required for reverse engine operation, and a single control means selectively operable to effect throttling of steam passing to the engine supply openings and to effect equal and opposite displacement of the sleeves in either direction.

SAMUEL LIPPINCO-TT GRISWOLD KNOX. 

